Mechanical sphincter for controlling urinary incontinence

ABSTRACT

A mechanical sphincter device is to be located in the body for engaging the urethra to control urinary incontinence. The device is formed by a curved piece of flexible material having free ends and a pair of juxtaposed strips of flexible material having their ends connected to the corresponding ends of the curved piece with the urethra disposed between opposing faces of the strips. When the curved piece is in a relaxed state it tensions the strips to apply pressure to the urethra therebetween to restrict flow of urine and when force is applied to the curved piece relaxing the tension on said pair of strips the pressure on the urethra is reduced and permits urine flow.

FIELD AND BACKGROUND OF THE INVENTION

As it is well known by those skilled in the medical field, urinaryincontinence is a serious urological problem, consisting in theincapacity of the individual to retain the urine, frequently causing theinvoluntary emission thereof.

Urinary incontinence may result from several factors (congenitaldiseases, acquired diseases, consequences from surgery, etc.). Among themost frequent causes, the following can be mentioned: prostatectomy(partial or total removal of the prostate); epispadias (congenitalmalformation in which the urethra opens before the end of the penis;injuries in the spinal medulla; fracture of the pelvis; neurogenicbladder, etc.

Undoubtfully, urinary incontinence causes significant impacts in thepatient's quality of life, since the involuntary emission of urine is adiscomfort, resulting in hygienic and social problems, provoking thereclusion of the patient, impairing his social and professionalactivities and very often his sexual performance.

Moreover, this disturbance usually brings emotional problems to thepatient, who becomes depressed and stigmatized.

Many studies involving several age groups revealed the prevalence fromabout 17 to 41% of urinary incontinence in the whole population of theplanet, consisting therefore in a public health problem. In the UnitedStates, for instance, more than 10 billion dollars are used yearly forthe treatment of urinary incontinence, this value surpassing thosevalues directed for the treatment of other diseases, such asrevascularization of the myocardium or dialysis.

Thus, it can be stated that urinary incontinence is a medical, socialand epidemiological problem with very important economic effects.

For all these reasons, urinary incontinence is one of the problems thathave been widely studied by many researchers, who are often frustratedfor not reaching solutions which are both technically and economicallyadequate for the problem. Such disease has also caused disappointment inmany surgeons, when said symptom arises as a sequella of surgicalprocedures.

Many have been the methods used for treating urinary incontinence, amongwhich the following can be mentioned: expectant therapy, pharmacologicaltreatment, electronic devices, several surgical procedures and, finally,artificial sphincters. Such methods have been employed in differentcircumstances and their results have received praises in some instances,but severe criticisms in others.

Many types of prosthesis have already been provided to treat urinaryincontinence, such as those from Foley (1947), Berry (1961), Kauffman(1973), Scott (1974) and Rosen (1976), besides Cunhinham's tweezers. Allthese models were constructed with the aim of causing urethralcompression. According to this basic principle, the mechanicalcompression systems were developed, until the artificial sphincters withself-regulating pressure were provided, such as the various modelsmanufactured by American Medical Systems.

The most modern system used nowadays is the AMS 800, also produced bythe above cited company and commercialized since 1983. This model ofsphincter comprises an inflatable sleeve, which is implanted in thepatient around his urethral canal and connected with a pump, whichcomprises a valve, a rechargeable delay resistor and a pressuredeactivating button. Said pump is also connected with a pressureregulating sump in the form of a balloon.

This artificial sphincter is kept constantly activated, i.e., the sleevesurrounding the urethra is kept permanently inflated, at a predeterminedpressure controlled by the sump, thus pressing the urethral canal andavoiding the passage of urine. Only when the patient presses thepressure deactivating button is that said sleeve is deflated, therebynot pressing the urethral canal anymore and, from that time on, allowingthe urine to pass. The emission of urine is thus controlled by thepatient with urinary incontinence.

One of the inconveniences of this current model of artificial sphincteris the large number of complex connections, which are difficult tohandle and increase the risk of mechanical dysfunctions. Anotherinconvenience resides in its implantation method, which requires a verylaborious and complicated surgery, with many details to be strictlyfollowed in order to avoid harmful intercourses, such as infections anderosions.

Another problem of this type of sphincter relates to the installationthereof, which requires skills, for example, to mount the system, todetermine the adequate pressure to obtain the continence, to knowexactly which details should be avoided so as not to result in thecomplications cited above and how to treat said complications when theyarise.

Finally, a very relevant aspect which limits the application of saidartificial sphincter in everyday practice is its cost. Unfortunately,this device is not accessible to all persons, since its value cannot bepaid by many patients. On the other hand, this high cost also imposeslimitations to the physician, who sees this type of therapeutics as theonly possible way of treatment.

DISCLOSURE OF THE INVENTION

With the aim to solve all these inconveniences and to achieve anadequate and objective option to correct and overcome all limitations ofthe known devices currently used, there has been provided a mechanicalsphincter for controlling urinary incontinence and its implantationmethod. This sphincter consists of a substantially simple device, whichis based on totally appliable physical principles, which can be easilyinstalled and which is manufactured in known biocompatible materials.Above all, it is a much more accessible option, on the economical pointof view, to a large number of patients, thus representing a veryimportant technological advance in this medical area.

The mechanical sphincter of the present invention consists of asemi-annular piece, which is made from any biocompatible materialpresenting a spring effect, such as nylon, polyester, steel, etc., andin whose free ends are affixed two strips or screens, parallely disposedto each other and made from any porous and anti-adherent biocompatiblematerial, such as nylon.

Said piece is implanted in the patient's urethra, just behind thescrotal region, said strips or screens being disposed surrounding saidurethra and being responsible for producing a urethral closing pressure,in order to guarantee the urinary continence. Said screens are notsubjected to shape or tensile alterations upon extending movements,thereby assuring a constant uniform pressure over the urethra. Moreover,since said screens are made from a porous material, they allow theformation of new vessels, which avoid ischemia in the urethra.

The method to implant the mechanical sphincter of the present inventionis also much more simpler than the conventional methods. It is onlynecessary to make a longitudinal trans-scrotal incision by planes, untilthe urethra is identified and dissected, surrounding it completely. Thebed for said screens is prepared and said screens are disposed aroundthe urethra and affixed to the ends of said semi-annular piece withstitches of prolene 0, or any other mechanical fixing means. At thismoment, the urethral closing pressure is set by means of a urethralprobe connected to an adequate conventional apparatus. Through atransversal abdominal incision, the bladder is identified and a plasticprobe is introduced therewithin. Then, physiological serum is infused,till a predetermined intravesical pressure has been reached. The urinarycontinence is tested after the present mechanical sphincter has beenimplanted.

Moreover, since the sphincter is implanted very close to the epidermis,the patient may easily find it and, with his fingers, press the ends ofthe semi-annular piece, one towards the other, in order to release thepassage of urine when desired, as explained below.

Thus, after the sphincter has been implanted, the patient will haveabsolute control over the emission of his urine, since both screens orstrips of the device will permanently exert a pressure around theurethra, sufficient to avoid the passage of urine. Only when the patientpresses said sphincter, more specifically the free ends of thesemi-annular piece, which are permanently tensioned by said screens orstrips is that the latter will be loosened, ceasing to press the urethraand consequently allowing the passage of urine. With the mechanicalsphincter of the present invention the problem of urinary incontinenceis fully solved in a less traumatic form to the patient, since theimplantation is achieved in a substantially simpler manner, itsutilization is very easy and practical and its cost is substantiallylower than that of the conventional devices.

BRIEF DESCRIPTION OF THE DRAWINGS

For illustrative purposes, the present invention will be describedbelow, with reference to the attached drawings, in which:

FIG. 1 is a perspective view of the mechanical sphincter of the presentinvention;

FIG. 2 is a schematic sectional view of the urethral canal of a patient,showing the implantation site of said sphincter;

FIG. 3 is a front view of the sphincter of the present invention in aresting position, in which the semiannular piece maintains both screensconstantly tensioned, thus pressing therebetween the patient's urethraand avoiding the passage of urine; and

FIG. 4 is the same front view, but now during the pressure exerted bythe patient on the semi-annular piece, more precisely at the endsthereof, which are pressed one towards the other, whereby the screensare loosened, ceasing to exert pressure around the urethra and allowingthe urine to pass.

BEST MODE FOR CARRYING OUT THE INVENTION

The objective of the present invention is to provide a mechanicalsphincter for controlling urinary incontinence and its implantationmethod, said sphincter (1) comprising a semi-annular piece (2) made fromany biocompatible material with a spring effect, such as nylon,polyester, steel, etc., in whose free ends are affixed two strips orscreens (3), parallely disposed to each other and made from any porousand anti-adherent biocompatible material, such as nylon.

Said sphincter (1) is implanted in the patient's urethra (u), justbehind the scrotal region, said strips or screens (3) being disposedsurrounding said urethra and being responsible for producing a urethralclosing pressure, in order to guarantee the urinary continence.

The method to implant the mechanical sphincter (1) of the presentinvention consists of making a longitudinal trans-scrotal incision byplanes, until the urethra (u) is identified and dissected, surroundingit completely. The bed for the screens (3) is prepared and said screensare disposed around the urethra and affixed to the ends of saidsemi-annular piece (2) with stitches of prolene 0, or any othermechanical fixing means. At this moment, the urethral closing pressureis set by means of a urethral probe connected to an adequateconventional apparatus. Through a transversal abdominal incision, thebladder is identified and a plastic probe is introduced therewithin.Then, physiological serum is infused, till a predetermined intravesicalpressure has been reached. The urinary continence is tested after thepresent mechanical sphincter has been implanted.

Thus, after said sphincter (1) has been implanted, the patient will haveabsolute control over the emission of his urine, since both screens orstrips (3) of the device will permanently exert a pressure around theurethra (u) disposed therebetween, said pressure being sufficient toavoid the passage of urine (see FIG. 3).

Only when the patient presses said sphincter (1), more specifically thefree ends of the semi-annular piece (2), which are permanently tensionedby said screens or strips (3), is that the latter will be loosened,ceasing to press the urethra and consequently allowing the passage ofurine (see FIG. 4).

We claim:
 1. A mechanical sphincter for controlling urinaryincontinence, comprising:a flexible curved piece of resilient materialto be located behind the scrotal region so as to be manually andexternally pressible, said curved piece having a pair of ends definingan open section and being deformable by the application of force tobring said ends closer together, and a pair of strips, one end of eachof said pair of strips connected to one of the ends of said curvedpiece, and the other end of each of said pair of strips connected to theother end of said curved piece, with said strips being disposed inopposing relationship one above the other when said strips are tensionedin a relaxed state of said resilient curved piece, and between which theurethra is to be disposed so as to remain under pressure, the tension ofsaid strips being removed and the strips separating when the ends ofsaid curved piece are brought closer together by manually deforming saidcurved piece to remove pressure on the urethra.
 2. A mechanicalsphincter as in claim 1 wherein at least one end of one said strip isadhesively connected to a respective end of said curved piece.
 3. Amechanical sphincter as in claim 1 wherein the material of said stripsis porous and non-adherent.
 4. A mechanical sphincter as in claim 1wherein the material of said strips is a screen.
 5. A mechanicalsphincter as in claim 1 wherein said curved piece is of semi-circularshape.
 6. A sphincter to be located in the body for engaging the urethrato control urinary incontinence comprising:a curved piece of resilientmaterial having a pair of spaced apart ends; and a pair of strips offlexible material, each of said strips having two ends with one of theends connected to one end of said curved piece and the other endsconnected to the other end of said curved piece with said pair of stripsjuxtaposed one above the other between said ends of said curved piece,the urethra to be disposed between opposing faces of said strips, saidcurved piece in a relaxed state tensioning said strips to apply pressureto the urethra therebetween to restrict flow of urine and force appliedto said curved piece relaxing the tension on said pair of strips toreduce the pressure on the urethra and permit urine flow.
 7. Amechanical sphincter as in claim 6 wherein at least one end of one ofsaid strips is adhesively connected to a respective end of said curvedpiece.
 8. A mechanical sphincter as in claim 6 wherein the material ofsaid strips is porous and non-adherent.
 9. A mechanical sphincter as inclaim 6 wherein the material of said strips is a screen.